1. Tonicia cuneata, n. sp. Plate XXVIII, figs. 1–2.

Shell oblong-ovate, rather small, valves much raised, the intermediate valves beaked, angled above, with cueiform sculpture. Anterior valve with 4 low and smooth ridges with serrated margins, corresponding with the slits, anterior margin with the same number of slightly projecting lobes, posterior margin a little concave; sculpture between the riblets consisting of deeply engraved grooves and punctures, leaving numerous wedge-shaped patches of various size; the whole surface dotted with minute eyes. Of the intermediate valves, the first is notably larger than the following 5, all are sinuated on the latero-anterior sides and narrowed, convex in front and prominently beaked behind; dorsal area V-shaped, smooth, microscopically transversely finely striate; pleural tracts with a few narrow longitudinal and divergent serrated grooves; lateral areas not raised, with an anterior obtuse diagonal ridge, sculpture similar to that of the head-valve; the small, reddish eyes scattered over the whole surface. Posterior valve with a V-shaped dorsal area, its sides serrated, mucro at about the posterior fourth, posterior slope moderately concave, posterior margin slightly lobed, the lobes corresponding with the slits; sculpture beautifully wedge-shaped, with the posterolateral ridges corresponding with the anterior slits; the whole surface covered with minute eyes. Girdle moderately broad, leathery, yellowish, almost naked, with very few silvery fine hairs near the margin. Colour a dirty-white; anterior valve with the riblets reddish-white, the grooves and punctures rusty; intermediate valves with the central area light-olive, bordered by white, ornamented with very fine longitudinal reddish lines; grooves on the pleural and lateral areas rusty, a few light-blue spots scattered over the areas; posterior valve having the central area coloured as the intermediate valves, the grooves rusty, the cuneiform nodules light-blue on the pleural tracts, white, with a few blue spots, posteriorly. Interior greenish-white,